A distasteful aspect of President Obama’s personality reared its head Wednesday, providing insight into why bipartisan success so often eludes him. Surrounded by family members of the Newtown victims, Obama charged that his foes had “willfully lied” to block “common-sense gun reform.”

Earlier this year, the president argued that Newtown survivors and other victims of gun violence “deserve a vote.” Yet as a former law professor should know, a vote doesn’t guarantee the outcome you want.

Alas, Obama has a hard time believing there can be honest disagreement with him. So he doesn’t spend much time trying to persuade. Instead, whether it’s the Supreme Court or a Republican he disagrees with, he impugns opponents in public.

That may help explain why this week the Senate had a gun bill that failed, even as a bipartisan compromise on immigration was announced: On immigration, Democrats wanted a deal, so they largely kept Obama out of it. On guns, he’s been front and center. Seems to make a difference.